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Ototoxicity of boric acid powder in a rat animal model
Murat Salihoglu1, Salim Dogru2, Enver Cesmeci3
1GATA Haydarpasa Training Hospital, Department of Otorhinolaryngology, Istanbul, Turkey.
Introduction:
Boric acid, which has antiseptic and acidic properties, is used to treat external and middle ear infections. However, we have not found any literature about the effect of boric acid powder on middle ear mucosa and inner ear.
Objective:
The purpose of this study is to investigate possible ototoxic effects of boric acid powder on cochlear outer hair cell function and histological changes in middle ear mucosa in a rat animal model.
Methods:
Twenty healthy, mature Wistar albino rats were used in this study. The rats were divided into two groups, Group A and Group B, each of which consisted of 10 rats. Initially, the animals in each group underwent distortion product otoacoustic emissions testing of their right and left ears. After the first distortion product otoacoustic emissions test, a surgical microscope was used to make a small perforation in both ears of the rats in each group, and a second distortion product otoacoustic emissions test was used to measure both ears in all of the rats. Boric acid powder was applied to the right middle ear of the rats using tympanic membrane perforation, and the distortion product otoacoustic emissions were measured immediately after the boric acid powder application. The histological changes and distortion product otoacoustic emissions were evaluated three days later in Group A and 40 days later in Group B.
Results:
No significant differences were found at all of the distortion product otoacoustic emissions frequencies. In Group A, mild inflammation of the middle ear mucosa was found on the third day after boric acid powder application. In Group B, boric acid powder caused mild inflammatory changes on the 40th day, which declined over time. Those changes did not lead to significant fibrosis within the mucosa.
Conclusion:
In rats, boric acid powder causes mild inflammation in middle ear mucosa and it has no ototoxic effects on cochlear outer hair cell function in the inner ear of rats.
Insights
Boric acid powder applied to rat ears caused mild middle ear inflammation but no inner ear damage. This study found no ototoxic effects on cochlear outer hair cell function.
Area of Science:
- Otolaryngology
- Pharmacology
- Toxicology
Background:
- Boric acid possesses antiseptic and acidic properties, commonly used for external and middle ear infections.
- Limited literature exists on the effects of boric acid powder on middle ear mucosa and inner ear structures.
Purpose of the Study:
- To investigate potential ototoxic effects of boric acid powder on cochlear outer hair cell function.
- To evaluate histological changes in the middle ear mucosa following boric acid powder application in a rat model.
Main Methods:
- Wistar albino rats were used, divided into two groups (n=10 each).
- Distortion product otoacoustic emissions (DPOAE) were measured before and after tympanic membrane perforation and boric acid powder application.
- Histological analysis of middle ear mucosa and DPOAE measurements were performed at 3 days (Group A) and 40 days (Group B) post-application.
Main Results:
- No significant differences in DPOAE across tested frequencies were observed, indicating no ototoxicity.
- Mild inflammation of the middle ear mucosa was noted on day 3 and day 40 post-application.
- Inflammatory changes were mild and did not result in significant mucosal fibrosis.
Conclusions:
- Boric acid powder application in rats leads to transient, mild inflammation in the middle ear mucosa.
- Boric acid powder does not exhibit ototoxic effects on the cochlear outer hair cell function in the inner ear of rats.
